﻿/*
 * Summary:
 *   A generic dictionary class that supports
 *   xml serialization
 *   
 * History:
 *   Date           Author      Changes
 *   13/11/2010     YIWEI YU    Created
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Xml.Serialization; /* for xml serialization */


namespace AcmeSportsStore
{
    /* 
     * <code
     *  remarks = "to create a serializable generic dictionary type
     *  because the dictionary provided by the framework is not
     *  xml-serializable.
     *  code referenced from an online technical article with some changes"
     *  reference_source_url 
     *  = "http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx"
     *  >
     */
    [XmlRoot("dictionary")]
    public class SerializableDictionary<TKey, TValue>
        : Dictionary<TKey, TValue>, IXmlSerializable
    {
        #region IXmlSerializable Members
        /*
             * this method might have to be implemented
             */
        public System.Xml.Schema.XmlSchema GetSchema()
        {
            return null;
        }

        /*
         * read the dictionary form source in xml format
         */
        public void ReadXml(System.Xml.XmlReader reader)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));

            bool wasEmpty = reader.IsEmptyElement;
            reader.Read();

            if (wasEmpty)
                return;

            while (reader.NodeType != System.Xml.XmlNodeType.EndElement)
            {
                reader.ReadStartElement("item");

                reader.ReadStartElement("key");
                TKey key = (TKey)keySerializer.Deserialize(reader);
                reader.ReadEndElement();

                reader.ReadStartElement("value");
                TValue value = (TValue)valueSerializer.Deserialize(reader);
                reader.ReadEndElement();

                this.Add(key, value);

                reader.ReadEndElement();
                reader.MoveToContent();
            }
            reader.ReadEndElement();
        }

        /*
         * write the dictionary out in xml format
         */
        public void WriteXml(System.Xml.XmlWriter writer)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));

            foreach (TKey key in this.Keys)
            {
                writer.WriteStartElement("item");

                writer.WriteStartElement("key");
                keySerializer.Serialize(writer, key);
                writer.WriteEndElement();

                writer.WriteStartElement("value");
                TValue value = this[key];
                valueSerializer.Serialize(writer, value);
                writer.WriteEndElement();

                writer.WriteEndElement();
            }
        }

        #endregion
    }
}
